VIABILITY AND FECUNDITY OF HUMAN SEMEN SPECIMENS CRYOSTORED AND TRANSPORTED AT 5°C USING THE BIO–TRANZTMSHIPPING

This study was designed to assess the viability and fecundity of semen stored at 5 degrees C for 24 hours using the Bio-Tranz shipping system. Semen specimens were assessed for motility and sperm membrane integrity at the time of collection and 24 hours after storage in the Bio-Tranz. In group 1 (n = 61), specimens were diluted in TYB, processed and used for intrauterine insemination (IUI), leaving an aliquot for storage for 24 hours in the Bio-Tranz. In group 2 (n = 67), specimens were diluted in TYB, stored for 24 hours in the Bio-Tranz and then processed and used for IUI. In both groups, the total motile sperm used for IUI was similar and the women that underwent IUI were standardized for ovulation prediction and time of insemination. The overall sperm characteristics between the two groups were within normal range. Significant decreases were noted in sperm motility and membrane integrity in both groups after storage. Similar pregnancy rates were obtained between the two patient populations. The use of the Bio-Tranz shipper is extremely convenient for patients requiring semen evaluation, cryostorage or IUI and other assisted reproductive technologies.

In-vitro developmental potential of individual mouse blastomeres cultured with and without zona pellucida: future implications for human assisted reproduction

This study was designed to compare the developmental potential of individual blastomeres derived from 2-, 4-, 6- and 8-cell mouse embryos cultured with and without zona pellucida (ZP). In the first series, one, three, five and seven blastomeres were biopsied from 2-, 4-, 6- and 8-cell embryos respectively, and inserted individually into empty ZP recipients, leaving the remaining blastomere within its original ZP. In the second series, the same protocol was used except that the biopsied blastomeres were cultured without ZP and compared with the remaining blastomere within its original ZP. For the first series, individual blastomeres derived from 2-, 4-, 6- and 8-cell embryos cultured with ZP showed blastocyst development of 82.4, 68.6, 44.4 and 23.1% respectively, with corresponding hatching rates of 70.6, 60.0, 25.9 and 7.7%. For the second series, individual blastomeres cultured without ZP progressed with blastocyst development of 73.3, 64.5, 35.7 and 22.7% respectively. Blastocyst multiplication was achieved most efficiently when using individual blastomeres from 4- and 6-cell embryos. This is the first report on comparative in-vitro propagation of single blastomeres derived from various cleavage stages in a mammalian species. Blastomere cloning with its multiple applications may be envisaged for human assisted reproductive technologies.

Efficient blastomere biopsy for mouse embryo splitting for future applications in human assisted reproduction

The objective of the current study was to establish a safe, efficient biopsy procedure for embryo splitting using the mouse model for future applications in human assisted reproduction. From mouse embryos at the 2-, 4-, 6- and 8-cell stage, half the number of blastomeres were microsurgically biopsied and transferred into empty mouse zonae pellucidae. Twin embryonic development was monitored during in-vitro culture. Blastocyst developmental rate using 2-, 4-, 6-, and 8-cell splitting was 74.4, 75.0, 66.7 and 38.4 respectively, with corresponding hatching rates of 94.9, 97.5, 92.7 and 83.8%. Blastocysts from 2-, 4-, and 6-cell splitting resulted in elevated hatching rates compared with non-operated blastocysts (87.5%), due to the Tyrode-assisted hatching effect. Blastocyst morphology was superior from 2- and 4-cell splitting when compared with 6- and 8-cell splitting. Furthermore, outgrowth of twin blastocysts from 2- and 4-cell splitting showed well-developed colonies with trophoblast cells and clusters of ICM cells, whereas those obtained from 6- and 8-cell splitting frequently formed small-sized colonies. Due to the high twinning success rate obtained under the experimental conditions employed in this study, it appears that with further modifications and proper safeguards, such embryo splitting efforts could have potential applications in humans.

Defining bioassay conditions to evaluate sperm/zona interaction: inhibition of zona binding mediated by solubilized human zona pellucida

OBJECTIVE

Our goal was to study the influence of solubilized human zonae pellucidae on zona binding potential and acrosome reaction.

MATERIALS AND METHODS

Zona pellucida (ZP) solutions were prepared by dissolving zona in acidic buffer, NaH2PO4 (pH 2.5), to obtain 0.1 and 0.5 zona pellucida/microliters. Zona binding capacity was evaluated by the addition of oocytes (10-fold) to sperm/zona pellucida solution droplets. The number of sperm bound to each oocyte was recorded. Zona pellucida-mediated acrosome activity was evaluated after 60 min of coincubation of sperm and 0.5 ZP/microliters.

RESULTS

The mean (+/- SE) number of sperm bound for control, 0.1 ZP/microliter, and 0.5 ZP/microliter was 181.2 +/- 12, 79.6 +/- 5, and 38.8 +/- 3, respectively. Zona pellucida-exposed sperm populations showed significant more acrosome-reacted sperm compared to control sperm, namely, 78 versus 32%, respectively (P = 0.001).

CONCLUSIONS

The observed zona binding inhibition might be ascribed to zona receptor blocking on the sperm surface or the inability of acrosome-reacted sperm to bind to the zona pellucida.

Comparison of motility characteristics and normal sperm morphology of human semen samples separated by percoll density gradient centrifugation

The aim of this study was twofold: to investigate the ability of Percoll gradient centrifugation (52, 68, 84%) to fractionate semen samples according to motility quality and percentage normal morphology and to determine whether there is an association between sperm motility quality and percentage normal morphology. Sperm motility was evaluated using a Hamilton Thorn analyzer and normal sperm morphology was manually assessed according to the strict criteria (< or = 4, 5-14, and >14%). The majority of motility parameters and the percentage normal morphology were found to be significantly improved in the 84% Percoll fraction. The greatest effect was on the < or = 4% group, shifting the mean normal morphology percentage from 2.6 to 5.2%. Curvilinear velocity (VCL) and average path velocity (VAP) were the only two motility parameters that were significantly associated with the percentage normal morphology. Using a combined VCL, VAP vector the >14% group was found to have a significantly different value as compared to the 5-14 and < or = 4% groups. Percoll (discontinuous) gradient centrifugation can therefore play a significant role in the improvement of semen samples for use in assisted reproduction procedures. The VCL, VAP vector identified may also serve as an additional tool in the prediction of the fertility potential of sperm samples.

Influence of elevated pH levels on structural and functional characteristics of the human zona pellucida: functional morphological aspects

PURPOSE

A total of 86 fresh and salt-stored immature human oocytes derived from postmortem ovarian tissue were used for this study.

METHODS

Oocytes were randomly incubated either in synthetic human tubal fluid medium (untreated zonae) or in a chemically defined medium (treated zonae).

RESULTS

Sperm binding experiments using hemizona assay conditions exhibited a 10-fold increased binding of sperm to treated compared to untreated oocytes (272.7 +/- 43 versus 24.3 +/- 15 sperm bound, respectively; P < 0.0001). pH recordings during incubation showed elevated pH levels of 8.1 compared to pH 7.2 among treated and untreated zonae, respectively. Ultrastructural examination showed a spongy appearance of the surface of treated zonae, whereas untreated zonae appeared compact with smooth surface.

CONCLUSIONS

The marked increase in sperm binding among treated zonae, together with the ultrastructural findings, suggest that the altered zona surface enhances sperm binding. The physiological maturational process of the zona pellucida might be manipulated in vitro, thus increasing sperm binding to the zona.

The influence of a mineral oil overlay on the zona pellucida binding potential of human spermatozoa

The objective of the study was to evaluate the effect of mineral oil on zona pellucida binding potential of human spermatozoa. The study compared zona binding using micro volume droplets under mineral oil as apposed to micro droplets in cryopreservation straws. Spermatozoa from eight proven fertile sperm donors were used. One hundred and fifty five matched hemizonae in 50 microliters, 100 microliters and 200 microliters insemination sperm droplets were co-incubated; (i) under mineral oil and (ii) 0.5 ml plastic cryopreservation straws. The results were analysed to determine the number of the zona bound spermatozoa during each experiment. Microvolumes with an oil overlay had a decrease in sperm bound per hemizona of 38% (mean +/- SD; 563 +/- 415 vs. 921 +/- 597), 51% (mean +/- SD; 392 +/- 359 vs. 800 +/- 566 sperm) and 18% (mean +/- SD; 502 +/- 369 vs. 618 +/- 445) in 200 microliters, 100 microliters and 50 microliters respectively, compared to microvolumes in cryopreservation straws. It was concluded that mineral oil may have some detrimental factors which interfere with zona binding of spermatozoa.

Development of a predictive model for optimal zona pellucida binding using insemination volume and sperm concentration

OBJECTIVE

To develop a predictive model under hemizona assay (HZA) conditions for human spermatozoa concentrations and insemination volume for optimum zona pellucida (ZP) binding.

DESIGN

Analysis of 20 different insemination volumes for zona binding and sperm morphology under HZA conditions.

SETTING

Reproductive biology unit, tertiary medical center.

PATIENTS

Four proven fertile sperm donors.

MAIN OUTCOME MEASURES

5-, 20-, 50-, 80-, and 100-microL droplets were analyzed with four different concentrations of 0.5 x 10(6), 1.0 x 10(6), 2.0 x 10(6), and 4.0 x 10(6) cells/mL to determine the number of sperm bound to each hemizona. Fifteen hemizonae were used for each insemination volume or microdroplet. Response surface regression model with volume and concentration as the regressor variables has been used.

RESULTS

The response surface of binding for the factors concentration and volume showed nonlinear association. A formula, indicating the optimal sperm insemination volume for maximum sperm binding to the ZP, Vmax = -(b1 + b5c)/2b6c, is described. The transformed data indicated 60 microL containing 4 x 10(6) sperm/mL to be optimal. Although morphology of zona spermatozoa is superior compared with seminal and postswim-up samples, no difference among the percentage of the normal morphology in different microdroplets could be demonstrated.

CONCLUSION

Optimal volume for the obtained concentration of spermatozoa from a patient can be calculated and therapeutically used for cases of severe oligozoospermic patients by microvolume inseminations in IVF practice.

Sperm binding capacity of human zona pellucida derived from oocytes obtained from different sources

The important contributions of sperm-oocyte interaction to infertility diagnostics is well established. Scientists are urged to search for methods to improve the assessment of gamete interaction. Sperm binding and penetration assays have frequented the literature, reporting on various aspects of sperm-oocyte interaction using either microbisected or whole human oocytes during the assay procedure. The objective of the study was to evaluate additional zona pellucida sources which can be used during zona binding studies. Hemizonae were obtained from the following oocytes: 1) experiment 1, prophase I oocytes from post-mortem ovarian tissue from different age groups namely, 7 months, 5 years, 7 years, 12 years and 30 years; 2) experiment 2 used donated immature Prophase I oocytes from the IVF treatment program and 3) experiment 3 evaluated zona binding for hemizonae which were previously used in hemizona assays. Results indicated that, in experiment 1, ovarian age does not have any influence on the zona pellucida's capacity to bind spermatozoa. The mean number of bound sperm among the different age groups did not differ significantly, namely 38.9 +/- 17 (7 months), 31.0 +/- 27 (5 years), 49.3 +/- 21 (7 years), 32.8 +/- 18 (12 years) and 39.5 +/- 17 (30 years). The pooled mean +/- SD binding for all the age groups in experiment 1 was 37.7 +/- 7. Likewise, the mean number of sperm bound (experiment 2) to zonae collected from oocytes using different ovulation induction regimes were 31.1 +/- 20 (unstimulated), 54.4 +/- 12 (HMG/HCG) and 15.3 +/- 9 (HMG alone).(ABSTRACT TRUNCATED AT 250 WORDS)

Sperm-oocyte interaction: studies on the kinetics of zona pellucida binding and acrosome reaction of human spermatozoa

Successful sperm-oocyte interaction depends, among other things, on sperm capacitation, which is defined by acrosomal and motility alterations. In the study described here the authors evaluated different aspects of this gamete interaction in humans. Specifically, the authors studied (1) the relationship between the number of spermatozoa bound to the zona pellucida and sperm concentration and incubation period, (2) the capacitation status and kinetics of acrosome reaction among the zona-bound spermatozoa, and (3) the effect of human follicular fluid on the zona-binding potential and acrosome status of spermatozoa from different men. The results indicated a concentration of 10(7) cells ml-1 after 15 min of coincubation to be the optimum for zona binding. The number of sperm bound after 0, 3 and 5 h of incubation was the same. In addition, spermatozoa incubated for 3 or 5 h underwent the acrosome reaction (range 9-43%) on the zona surface within 15 min of binding. The maximum percentage of acrosome-reacted spermatozoa was reached after 60 min of binding. Follicular fluid affected the sperm populations selectively, since it did not influence zona binding capacity in all cases. The data enhances the authors' understanding of critical events occurring before fertilization.

The effect of pentoxifylline on sperm movement characteristics and zona pellucida binding potential of teratozoospermic men

This study investigates the effect of pentoxifylline on sperm movement and zona pellucida binding. Spermatozoa from nine teratozoospermic patients (10.2 +/- 6% normal forms) were included in the study. Test samples were diluted with a 4 nM solution of pentoxifylline, and control samples with Ham's F-10 culture medium only. Zona pellucida binding potential was measured under hemizona assay conditions (HZA). Sperm motility was evaluated at the start (0 h post-swim-up) and end (4 h) of the HZA, under test-tube conditions and under HZA conditions (50 microliters droplet under oil). Motility parameters tested included the curvilinear velocity (VCL), straight line velocity (VSL) and linearity (LIN). Compared to the controls, pentoxifylline-treated samples showed an immediate stimulation of sperm motility, under test-tube conditions, with a significant elevation of VCL at 0 h incubation (102.77 +/- 14.4 versus control value 84.60 +/- 10.6 microns/s; P = 0.005), which however was reversed after 4 h incubation (73.16 +/- 4.6 versus control value 85.47 +/- 12.8 microns/s; P < 0.005). A decline in sperm motility from 0 to 4 h incubation was noted for all the pentoxifylline-treated samples, under both test tube conditions (VCL: 102.77 +/- 14.4 versus 73.16 +/- 4.6 microns/s, P < 0.005; VSL: 27.2 +/- 10 versus 10.66 +/- 2.2 microns/s, P < 0.005; LIN: 23.65 +/- 7.1 versus 11.86 +/- 1.8%, P < 0.005) and HZA conditions (VCL: 100.04 +/- 13.1 versus 76.00 +/- 7 microns/s, P < 0.005; VSL: 26.40 +/- 8.7 versus 9.14 +/- 4.5 microns/s, P < 0.005; LIN: 26.2 +/- 12 versus 11.05 +/- 4.3%, P < 0.005).(ABSTRACT TRUNCATED AT 250 WORDS)

The relationship between morphology, motility and zona pellucida binding potential of human spermatozoa

Prediction of the fertilizing potential of human gametes under in vitro conditions has been a major field of interest of assisted reproductive programmes. However, sperm morphology has been regarded as a predictor of human in vitro fertilization rate. This paper prospectively evaluates the relationships among normal sperm morphology and (1) motion characteristics viz. curvilinear velocity (VCL), straight line velocity (VSL), and linearity (LIN) (n = 37) and (2) sperm-zona pellucida binding capacity under HZA conditions (n = 144) of two separate groups of infertile couples. Semen was evaluated for sperm concentration, percentage motility, forward progression, and percentage normal morphology (strict criteria). The motility characteristics were measured using a computerized Sperm Motility Quantifier (SMQ). The zona binding potential of sperm was evaluated using the hemizona assay. Firstly, the VCL significantly differed between the P-pattern and both the G (72.9 +/- 7 vs. 86.3 +/- 16 microns s-1; P = 0.04) and N patterns (72.9 +/- 7 vs. 91.0 +/- 15 microns s-1; P = 0.002). The VSL differed only between the P and N patterns, being 19.7 +/- 7 vs. 32.6 +/- 15 microns s-1 (P = 0.02), respectively. No significant differences in LIN were noted between any of the three patterns. The sperm concentration differed significantly between the P and both the G (37.9 +/- 35 vs. 80.8 +/- 9 x 10(6) ml-1; P = 0.03) and the N patterns (37.9 +/- 35 vs. 89.7 +/- 72 x 10(6) ml-1; P = 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)